Support, flexibility and light weight are three important considerations in the design of athletic shoes.
First, support provides that the sole of a shoe be securely attached to the wearer's foot, without significant displacement of the sole relative to the foot, even under substantial force. Support strength is compromised when a shoe's structural materials or closure apparatus stretches under significant loads, or stretches or weakens over time, resulting in an undesirably loose fit. Strength also generally provides durability of support over long-term use.
Second, flexibility in a shoe is desirable because it provides comfort to the wearer and is generally believed to provide better athletic performance, fewer injuries, and better overall health. Ideally, a shoe would be sufficiently flexible so as not to significantly restrict natural foot movements.
Third, it is also desirable to minimize the weight of a shoe for several reasons. Athletic performance is improved by reducing the amount of energy that goes into carrying the shoe's weight, and manipulating it during athletic activities. Also, a lighter shoe generally correlates with reduced material costs and lower shipping costs.
Conventional shoe designs must weigh a trade-off between the benefits of improved support, against the accompanying disadvantages of reduced flexibility and increased weight in a strengthened shoe. Conversely, conventional shoes have been designed for very light weight and great flexibility, but with a sacrifice in support, making them unsuitable for long-term vigorous athletic activities that create substantial shoe forces. In addition, such low strength shoes tend to wear out prematurely or fail during use.
Current shoe designs generally have "uppers" constructed as substantially unbroken expanses of leather, synthetic fabric, or the like. These solid sheets of material are generally flexible as two dimensional sheets. However, when sewn in a three dimensional form, they become more resistant to flexing. Because the solid panels of material carry loads distributed across their entire areas, they must remain largely unbroken to preserve strength. Such solid panels have limited flexibility. Ventilation is limited to the permeability of the material or to a minimal amount of perforation.
From the foregoing, it will be recognized that there is a need for an athletic shoe that overcomes these drawbacks of the prior art by providing a structure that is sufficiently strong to durably bear substantial loads and resist stretching, while providing a light weight shoe that is flexible for comfort and performance, and which provides for adequate foot ventilation. The present invention satisfies this need.
By providing a shoe upper having a plurality of panels, each of which is secured at a lower edge to the sole of the shoe, and has an arc-shaped upper edge including a high strength flexible loop of cable secured at each of its ends to the sole of the shoe underneath the wearer's foot. Because the cable bears the majority of the load, each panel may be perforated with large openings for ventilation, to facilitate flexibility, and to provide an aesthetic appearance, without impairing strength. The cable may be exposed in places along the upper edge of the panel so that shoelaces may be looped around the cable to draw together the cables on the medial and lateral sides of the shoe, securing the sole to the wearer's foot.
The foregoing and additional features and advantages of the present invention will be more readily apparent from the following detailed description which proceeds with reference to the accompanying drawings.